Table 2.
Selected Characteristics of the Study Population
| Cases (n=1,806) | Sibling Controls (n=2,879) | |
|---|---|---|
| Person Characteristic | ||
| Mean Age ± SD | 53.5± 10.9 | 54.0 ± 11.8 |
| Sex, No. (%) | ||
| Male | 927 (51.3) | 1278 (44.4) |
| Female | 879 (48.7) | 1601 (55.6) |
| Race, No. (%) | ||
| Non-Hispanic White | 1580 (87.5) | 2512 (87.3) |
| Black | 32 (1.8) | 42 (1.5) |
| Asian | 69 (3.8) | 113 (3.9) |
| Other† | 104 (5.8) | 189 (6.6) |
| Unknown/Missing | 21 (1.2) | 23 (0.8) |
| Center, No. (%) | ||
| Ontario, Canada | 308 (17.1) | 515 (17.9) |
| USC Consortium, U.S. | 384 (21.3) | 519 (18.0) |
| Melbourne, Australia | 344 (19.0) | 611 (21.2) |
| Hawaii, U.S. | 63 (3.5) | 103 (3.6) |
| Mayo Foundation, U.S. | 282 (15.6) | 526 (18.3) |
| Seattle, U.S. | 425 (23.5) | 605 (21.0) |
| Family History of CRC, No. (%) | ||
| No 1st degree relative | 1177 (65.2) | - |
| At least 1 1st degree relative | 546 (30.2) | |
| Unknown/Missing | 83 (4.6) | |
| Alcohol use (drinks/wk) | ||
| None | 467 (25.9) | 829 (28.8) |
| 1–7 (moderate) | 857 (47.5) | 1353 (47.0) |
| 8+ (heavy) | 229 (12.7) | 362 (12.6) |
| Unknown/Missing | 253 (14.0) | 335 (11.6) |
| Folate supplements‡ | ||
| No | 1586 (87.8) | 2557 (88.8) |
| Yes | 196 (10.9) | 274 (9.5) |
| Unknown/Missing | 24 (1.3) | 48 (1.7) |
| Multivitamins‡ | ||
| No | 820 (45.4) | 1497 (52.0) |
| Yes | 971 (53.8) | 1346 (46.8) |
| Dietary folate (µg/d) (Mean ± SD)§ | 327.4 ± 118.7 | 334.1 ± 126.8 |
| Total folate (DFE/d) (Mean ± SD)¶ | 477 ± 265.6 | 525.4 ± 439.7 |
| Dietary B12(µg/d) (Mean ± SD)* | 3.0 ± 1.2 | 2.9 ± 1.3 |
| Total B12(µg/d) (Mean ± SD)£ | 6.2 ± 6.4 | 7.4 ± 11.8 |
| Dietary B6 (mg/d) (Mean ± SD)* | 1.1 ± 0.4 | 1.1 ± 0.4 |
| Total B6 (mg/d) (Mean ± SD)£ | 1.9 ± 2.0 | 2.3 ± 3.8 |
| Tumor Characteristics | ||
| Site, No. (%) | ||
| Right Colon | 598 (33.1) | - |
| Left Colon | 525 (29.1) | |
| Rectum | 593 (32.8) | |
| Unknown/Missing | 90 (5.0) | |
| MSI, No. (%) | ||
| MSS | 855 (47.3) | - |
| MSI-L | 151 (8.4) | |
| MSI-H | 179 (9.9) | |
| Unknown/Missing | 621 (34.4) |
†
includes individuals who self-identified themselves as Hispanic, Native, Hawaiian/Pacific Islander and Mixed Race.
‡
Ever use of supplements at least 2x/week for more than a month.
§
Calorie adjusted, calculated from food frequency questionnaire as dietary folate equivalents using post-fortification food composition tables (N cases=585; N controls=837).
¶
Calorie adjusted, sum of dietary and supplement use (as dietary folate equivalents) from food frequency questionnaire (N cases=585; N controls=837).
*
Calorie adjusted, calculated from food frequency questionnaire.
£
Calorie adjusted, sum of dietary and supplement use from food frequency questionnaire.